A continuously variable transmission for a vehicle which is operated in a manual operation mode as well as in an automatic operation mode is disclosed in Tokkai Hei 9-196156 published in 1997 by the Japanese Patent Office.
The transmission is provided with a speed ratio controller so as to control the speed ratio of the transmission. The speed ratio controller stores a map defining plural fixed target speed ratios corresponding to various speed ratio grade any of which may be selected by a driver via a selector lever.
When in the manual operation mode, the controller looks up this map for finding the target speed ratio corresponding to the selected speed ratio grade and feedback controls the speed ratio of the transmission such that it coincides with the target speed ratio found in the map. With this controller, therefore, the continuously variable transmission may act as a quasi-manual transmission.